1. Field of the Invention
The present invention relates to carbon nanotube-based devices and methods for making such devices. The application relates to a contemporaneously filed application titled “CARBON NANOTUBE-BASED DEVICE AND METHOD FOR MAKING THE SAME” and having the same applicants and the same assignee with the instant application.
2. Description of Related Art
Carbon nanotubes have electrical conductance relate to their structure and chemically stable. Carbon nanotubes typically have very small diameters (less than 100 nanometers) and large aspect ratios (length/diameter). Due to these and other properties, it has been suggested that carbon nanotubes will play an important role in fields such as nano-scale integrate circuits, field emission, and single electronic components such as single electronic transistors. Recently, some electronic components based on a single carbon nanotube have been made in laboratories, such components including a field effect transistor, a logic circuit and a memory. The characteristics of these components are being actively researched. For example, a nanotube transistor is reported in an article by Sander J Tans et al. entitled “Room-temperature transistor based on a single carbon nanotube” (Nature 393–49, 1998). However, synthesis of large amounts of carbon nanotubes having practical applications depends in large part on manufacturing techniques developed using a bottom-up approach.
Manufacturing techniques using the bottom-up approach can control the position, direction, and size of carbon nanotubes. Desired configurations for target nano-scale components can be obtained using relatively few and relatively economical formation steps. A method of controlling the position of carbon nanotube growth by distributing a patterned catalyst is reported in an article by Fan S. S. et al. entitled “Self-oriented regular [sic] of carbon nanotubes and their field emission properties” (Science Vol. 283, pp.512–514, Jan. 22, 1999). In said method, the obtained carbon nanotubes extend perpendicularly to a plane of a substrate.
In addition, a method for controlling the growth of aligned nanotubes in several directions in a single process is reported by B. Q. Wei et al. in an article entitled “Organized assembly of carbon nanotubes” (Nature Vol. 416, pp. 495–496, Apr. 4, 2002).
However, in all the above-mentioned methods, it is not possible to properly control a direction in which the aligned nanotubes extend.
A method to control the direction of single-walled carbon nanotube growth is reported in an article by Yue-gang Zhang et al. entitled “Electric-field-directed growth of aligned single-walled carbon nanotubes” (Applied Physics Letters, Vol. 79, Number 19, Nov. 5, 2001).
However, Zhang et al. method was a wide area control, all the carbon nanotubes in a particular region tend to growth in the same direction as that of the electric field. It is difficult to realize localized and versatile direction control by any external field like an electric field. This limits the diversified design of carbon nanotube-based structures.